Yesterday ARM announced that five other major chip manufactures including Fujitsu Semiconductor and MediaTek have licensed its big.LITTLE architecture. Now the company has started showing off what the new architecture can do when placed in Samsung’s hands. To do this it has been demonstrating a prototype tablet using the Samsung Exynos 5 Octa at its Mobile World Congress (MWC) booth in Barcelona.
The demo cycles through some “real world” work loads, like browsing and using Google maps, and shows which cores are being used (Cortex-A7 or Cortex A-15) and how much energy is being consumed. What is interesting about the demo is seeing how much the Exynos 5 Octa favors the power friendly A7 cores. The big.LITTLE architecture isn’t a half baked system where the CPU moves to the A7 cores when it is generally idle. The switching between cores is frequent and the Cortex-A15 is only used when necessary. During the most intensive part of the demo, the A15 cores where used almost exclusively, but during tasks like browsing the A15 cores just blipped into life momentarily before the A7 cores took over again.
If ARM has managed to engineer the architecture in such a way that the context switch from one core to another isn’t too expensive, and we can assume they have, then big.LITTLE looks brilliant!